If your customer has a vented crawlspace with insulated ducts and no pipes, they likely have noticed their cold and noisy floors. The best solution for both the thermal and acoustical problems is to insulate the floor above the crawlspace.
The Owens Corning QuietZone® Acoustic System reduces the level of unwanted noise transmitted in the home while maintaining the desired level of comfort. Our QuietZone® Acoustic Floor Mat is acoustically engineered to isolate sound. Placed between the subfloor and a plywood or gypsum concrete overlayment, it forms an isolation layer for sound vibrations and impact noises such as foot traffic.
For complete acoustic performance, use with Owens Corning QuietZone® acoustic batts, which absorb sound vibrations within the wall cavity. They provide excellent in-place acoustical performance, and are as easy to install as thermal insulation.